Clinical outcome of patients with orbital fractures treated with patient specific CAD/CAM ceramic implants - A retrospective study

Orbital Patient-Specific (Customized) Implants: A Report by the American Academy of Ophthalmology

PURPOSE

To review systematically the literature on the efficacy and safety of the use of patient-specific implants (PSIs) in orbital reconstructive surgery.

METHODS

A literature search was last conducted in January 2025 in the PubMed database for English language original research that assessed the use of any PSI reported for orbital reconstructive surgery. Of the 219 articles identified, 51 met the inclusion criteria for this assessment and were selected for full-text review and data abstraction. A total of 19 studies met the study criteria, and the panel methodologist assigned a level III rating to each study.

RESULTS

No study met the criteria for level I or II evidence. Eight of the 19 studies compared a PSI group with a control group (other forms of implants such as preformed, prebent sheets)-5 studies involved acute fracture repair and 3 involved a mixture of acute, delayed, or revision surgery. The remaining 11 studies did not have a comparison group, and indications included acute fracture repair (n = 2), delayed or secondary fracture repair (n = 3), or an after-tumor resection (n = 5). One study compared outcomes using PSIs designed using automated software with PSIs designed manually. Patient-specific implant material included titanium (n = 12), polyether ether ketone (PEEK) (n = 3), porous polyethylene (n = 2), and ceramic (n = 2). Time to manufacture implants ranged from 1 to 35 days, with most under 10 days. Volumetric analysis generally reported greater improvement in postoperative orbital volume for PSIs compared with non-PSIs. Clinical improvement in diplopia, enophthalmos, and extraocular motility was variably reported and largely not statistically analyzed or significant. Complications were variably reported and included expected complications after orbital fracture repair.

CONCLUSIONS

The existing literature on PSIs for orbital surgery contains a heterogeneity of indications, designs, materials, and reporting. Because all studies met level III criteria for evidence, definitive conclusions were limited. Although anecdotal and low-quality evidence reports showed possible improved outcomes with PSIs compared with non-PSIs, determination of the best applications, designs, outcomes, and safety will require well-designed prospective studies with sufficient postoperative follow-up and outcome metrics.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Calcium sulfate-based load-bearing bone grafts with patient-specific geometry

The treatment of bone defects with complex three-dimensional geometry presents challenges in terms of bone grafting and restoration. In this paper, we propose a rapid and effective method that uses 3D printing, ceramic casting, and the incorporation of mesh reinforcement to create load-bearing bone grafts with patient-specific three-dimensional geometry. Using two types of facial bones as examples, we show that this fabrication method has a high degree of geometrical fidelity. We also experimentally study the fracture behavior of six different architectures designed for the treatment of mandibular defects, one of the principal load-bearing facial bones. These design configurations include un-reinforced calcium sulfate samples, and samples reinforced with one or two layers of stainless steel, poly (lactic acid), and poly (L-lactic acid). The results suggested a trade-off between energy dissipation and maximum load based on the position of the metal mesh in the sample. Samples reinforced with one layer of metallic mesh at their lowermost margin exhibited a 17% higher stiffness and a 21.3% higher peak load, while samples with a layer of metal mesh embedded within dissipated 16% more energy. Samples with two layers of metallic mesh demonstrated the highest improvements among all samples, dissipating 5767.85% more energy and exhibiting a peak load 145.6% higher compared to plain CS. The improvements in stiffness for SD, SL, and S2 were 3%, 21.3%, and 21.9% respectively compared to the plain ceramic. In contrast, PLA mesh improved energy dissipation by 96.71% but reduced the peak load by 29.18%, while PLLA mesh decreased both the peak load and the dissipated energy by 13.05% and 35.31%, respectively. While PLA mesh reduced stiffness by 11% compared to plain CS, PLLA mesh-reinforced samples were slightly stiffer than pure CS by 1.6%.

Clinical and radiographic assessment of patient-specific transantral reconstruction of orbital floor fractures: A case series

To clinically and radiographically evaluate patient-specific titanium meshes via a trans-antral approach for correction of enophthalmos and orbital volume in patients with recent unilateral orbital floor fracture. Seven patients with unilateral orbital floor fractures received patient-specific titanium meshes that were designed based on a mirror-image of the contralateral intact orbit. The patient-specific implants (PSIs) were inserted via a trans-antral approach without endoscopic assistance. The patients were evaluated clinically for signs of diplopia and restricted gaze as well as radiographically for enophthalmos and orbital volume correction. Diplopia was totally resolved in two of the three patients who reported diplopia in the upward gaze. Whereas enophthalmos significantly improved in all but two patients, with a mean value of 0.2229 mm postoperatively compared to 0.9914 mm preoperatively. CT scans showed excellent adaptation of the PSIs to the orbital floor with a mean reduction of the orbital volume from 29.59 cc to 27.21 cc, a mean of 0.6% smaller than the intact orbit. It can be concluded that the proposed PSI can offer good reconstruction of the orbital floor through an isolated intraoral transantral approach with minimal complications. It could of special benefit in extensive orbital floor fractures.

An innovative 3D hydroxyapatite patient-specific implant for maxillofacial bone reconstruction: A case series of 13 patients

The study aimed to evaluate and discuss the use of an innovative PSI made of porous hydroxyapatite, with interconnected porosity promoting osteointegration, called MyBone Custom® implant (MBCI), for maxillofacial bone reconstruction. A multicentric cohort of 13 patients underwent maxillofacial bone reconstruction surgery using MBCIs for various applications, from genioplasty to orbital floor reconstruction, including zygomatic and mandibular bone reconstruction, both for segmental defects and bone augmentation. The mean follow-up period was 9 months (1-22 months). No infections, displacements, or postoperative fractures were reported. Perioperative modifications of the MBCIs were possible when necessary. Additionally, surgeons reported significant time saved during surgery. For patients with postoperative CT scans, osteointegration signs were visible at the 6-month postoperative follow-up control, and continuous osteointegration was observed after 1 year. The advantages and disadvantages compared with current techniques used are discussed. MBCIs offer new bone reconstruction possibilities with long-term perspectives, while precluding the drawbacks of titanium and PEEK. The low level of postoperative complications associated with the high osteointegration potential of MBCIs paves the way to more extensive use of this new hydroxyapatite PSI in maxillofacial bone reconstruction.

Altered brain network centrality in patients with orbital fracture: A resting‑state functional MRI study

The present study aimed to investigate potential functional network brain-activity abnormalities in individuals with orbital fracture (OF) using the voxel-wise degree centrality (DC) technique. The present study included 20 patients with OF (12 males and 8 females) and 20 healthy controls (HC; 12 males and 8 females), who were matched for gender, age and educational attainment. Functional magnetic resonance imaging (fMRI) in the resting state has been widely applied in several fields. Receiver operating characteristic (ROC) curves were calculated to distinguish between patients with OF and HCs. In addition, correlation analyses were performed between behavioral performance and average DC values in various locations. The DC technique was used to assess unprompted brain activity. Right cerebellum 9 region (Cerebelum_9_R) and left cerebellar peduncle 2 area (Cerebelum_Crus2_L) DC values of patients with OF were increased compared with those in HCs. Cerebelum_9_R and Cerebelum_Crus2_L had area under the ROC curve values of 0.983 and 1.000, respectively. Patients with OF appear to have several brain regions that exhibited aberrant brain network characteristics, which raises the possibility of neuropathic causes and offers novel therapeutic options.

Automatic orbital segmentation using deep learning-based 2D U-net and accuracy evaluation: A retrospective study

The purpose of this study was to verify whether the accuracy of automatic segmentation (AS) of computed tomography (CT) images of fractured orbits using deep learning (DL) is sufficient for clinical application. In the surgery of orbital fractures, many methods have been reported to create a 3D anatomical model for use as a reference. However, because the orbit bone is thin and complex, creating a segmentation model for 3D printing is complicated and time-consuming. Here, the training of DL was performed using U-Net as the DL model, and the AS output was validated with Dice coefficients and average symmetry surface distance (ASSD). In addition, the AS output was 3D printed and evaluated for accuracy by four surgeons, each with over 15 years of clinical experience. One hundred twenty-five CT images were prepared, and manual orbital segmentation was performed in all cases. Ten orbital fracture cases were randomly selected as validation data, and the remaining 115 were set as training data. AS was successful in all cases, with good accuracy: Dice, 0.860 ± 0.033 (mean ± SD); ASSD, 0.713 ± 0.212 mm. In evaluating AS accuracy, the expert surgeons generally considered that it could be used for surgical support without further modification. The orbital AS algorithm developed using DL in this study is extremely accurate and can create 3D models rapidly at low cost, potentially enabling safer and more accurate surgeries.

Are Magnetic Resonance Imaging-Generated 3Dimensional Models Comparable to Computed Tomography-Generated 3Dimensional Models for Orbital Fracture Reconstruction? An In-Vitro Volumetric Analysis

BACKGROUND

Magnetic resonance imaging (MRI) is being increasingly considered as an alternative for the evaluation and reconstruction of orbital fractures. No previous research has compared the orbital volume of an MRI-imaged, three-dimensional (3D), reconstructed, and virtually restored bony orbit to the gold standard of computed tomography (CT).

PURPOSE

To measure the orbital volumes generated from MRI-based 3D models of fractured bony orbits with virtually positioned prebent fan plates in situ and compare them to the volumes of CT-based virtually reconstructed orbital models.

STUDY DESIGN

This retrospective in-vitro study used CT and MRI data from adult patients with orbital trauma assessed at the Royal Brisbane and Women's Hospital Outpatient Maxillofacial Clinic from 2011 to 2012. Only those with orbital blowout fractures were included in the study.

PREDICTOR VARIABLE

The primary predictor variable was imaging modality, with CT- and MRI-based 3D models used for plate bending and placement.

MAIN OUTCOME VARIABLE

The primary outcome variable was the orbital volume of the enclosed 3D models.

COVARIATES

Additional data collected was age, sex, and side of fractured orbit. The effect of operator variability on plate contouring and orbital volume was quantified.

ANALYSES

The Wilcoxon signed rank test was used to assess differences between orbital volumes with a significance level P < .05.

RESULTS

Of 11 eligible participants, six patients (four male and two female; mean age 31 ± 8.6 years) were enrolled. Two sets of six CT-based virtually restored orbits were smaller than the intact contralateral CT models by an average of 1.02 cm3 (95% CI -0.07 to 2.11 cm3; P = .028) and 0.99 cm3 (95% CI 0.07 to 1.91 cm3; P = .028), respectively. The average volume difference between the MRI-based virtually restored orbit and the intact contralateral MRI model was 0.97 cm3 (95% CI -1.08 to 1.94 cm3; P = .75). Imaging modality did affect orbital volume difference for 1 set of CT and MRI models (0.63 cm3; 95% CI -0.11 to 1.29 cm3; P = .046) but not the other (0.69 cm3; 95% CI -0.11 to 1.23 cm3; P = .075). Single operator variability in plate bending did not result in significant (P = .75) volume differences.

CONCLUSIONS

MRI can be used to reconstruct orbital volume with a clinically acceptable level of accuracy.

A Case Report of Zygomatic Fracture Reconstruction: Evaluation with Orbital Measurements and Models Registration

The repair and reconstruction of defects in the craniomaxillofacial region can be particularly challenging due to the complex anatomy, individuality of each defect, and sensitivity of the involved systems. This study aims to enhance the facial appearance and contribute to the reconstruction of the zygomatic arch. This was achieved through virtual planning of the surgery and assessment of clinical matching, including orbital measurements and registration of numerical models. A three-dimensional design of a young female case was generated on a skull model using Mimics® software, and the orbit was isolated using 3-Matic® to assess the reconstructive effect. 3D-printed implants were then surgically placed on the injured region, and Netfabb® software was used to make a virtual registration between the numerical models before and after the intervention. This allowed for the calculation of a deviation of 7 mm, equivalent to 86.23% of the shape restoration rate, to assess the success of the surgery. The computerized method enabled a precise design of the needed plates and analysis of the fixation places, resulting in a satisfactory cosmetic and functional outcome for the patient with minimal complications and good implant stability. Notably, a significant difference was observed in the orbital frontal area after 3 months of surgery (p < 0.001). Within the limitations of the study, these results suggest that virtual planning and customized titanium implants can serve as useful tools in the management of complex zygomatic-orbital injuries.

Accuracy of intraoperative navigation for orbital fracture repair: A retrospective morphometric analysis

In this retrospective case series, patients undergoing surgery to treat isolated orbital floor fractures were morphometrically analyzed. Cloud Compare was used to compare mesh positioning with a virtual plan, using the distance-to-nearest-neighbor method. To assess the accuracy of mesh positioning, a mesh area percentage (MAP) parameter was introduced and three distance ranges were defined as the outcome measures: the 'high-accuracy range' included MAPs at a distance of 0-1 mm from the preoperative plan; the 'intermediate-accuracy range' included MAPs at a distance of 1.1-2 mm from the preoperative plan; the 'low-accuracy range' included MAPs at a distance of >2 mm from the preoperative plan. To complete the study, morphometric analysis of the results was combined with clinical judgment ('excellent', 'good', or 'poor') of mesh positioning by two independent blind observers. In total, 73 of 137 orbital fractures met the inclusion criteria. In the 'high-accuracy range' the mean, minimum, and maximum MAP values were 64%, 22%, and 90%, respectively. In the 'intermediate-accuracy range', the mean, minimum, and maximum values were 24%, 10%, and 42%, respectively. In the 'low-accuracy range', the values were 12%, 1%, and 48%, respectively. Both observers classified 24 cases of mesh positioning as 'excellent', 34 as 'good', and 12 as 'poor'. Within the limitations of the study, it seems that virtual surgical planning and intraoperative navigation has the potential to add quality to the repair of the orbital floor and, therefore, should be taken into consideration whenever appropriate.

Primary reconstruction of combined orbital and zygomatic complex fractures with patient-specific milled titanium implants - A retrospective study

The aim of this retrospective study was to compare mid-facial symmetry and clinical outcomes between patients treated with patient-specific and standard implants in primary fracture reconstructions of combined orbital and zygomaticomaxillary complex fractures. Patients who underwent primary reconstruction of orbital and zygomaticomaxillary complex fractures during the study period were identified and background and clinical variables and computed tomography images were collected from patient records. Zygomaticomaxillary complex dislocation and orbital volume were measured from pre- and postoperative images and compared between groups. Out of 165 primary orbital reconstructions, eight patients treated with patient-specific and 12 patients treated with standard implants were identified with mean follow-up time of was 110 days and 121 days, respectively. Postoperative orbital volume difference was similar between groups (0.2 ml for patient-specific vs 0.3 ml for standard implants, p = 0.942) despite larger preoperative difference in patient-specific implant group (2.1 ml vs 1,5 ml, p = 0.428), although no statistical differences were obtained in symmetricity or accuracy between the reconstruction groups. Within the limitations of the study it seems that patient-specific implants are a viable option for primary reconstructions of combined zygomaticomaxillary complex and orbital fractures, because with patient-specific implants at least as symmetrical results as with standard implants can be obtained in a single surgery.

[Current developments in primary and secondary surgical treatment of midface and periorbital trauma]

Fractures of the periorbita and the midface are among the most common bony facial injuries. Aesthetic and functional reconstruction is a challenge in clinical routine. This article illustrates recent developments in the primary and secondary surgical treatment of midface and periorbital trauma. Resorbable patches and films increase the anatomic reconstructive capacity and enable treatment of extensive orbital fractures. Orbital fractures with involvement of supporting key structures are advantageously reconstructed using patient-specific implants (PSI), which are fabricated by computer-assisted manufacturing techniques and positioned by intraoperative navigation. If late complications such as bulbar malposition and enophthalmos have occurred after the initial procedure, they can be addressed by overcorrective restoration of orbital volume. The use of PSI for initial fracture restoration of the midface is not yet established but may be useful in re-osteotomies of misconsolidated fragments. Extensive midface defects with significant soft tissue involvement can be reconstructed using microvascular grafts. Consecutive reconstructive procedures may include orthognathic surgery and local flap reconstruction. In summary, the integration and advancement of computer-assisted techniques now offers individualized reconstruction procedures, which may be a viable alternative to conventional implants and compression miniplates. Future developments may focus on the search for innovative biomaterials, which can be integrated into computer-aided design and manufacturing processes.

Personalized Medicine Workflow in Post-Traumatic Orbital Reconstruction

Restoration of the orbit is the first and most predictable step in the surgical treatment of orbital fractures. Orbital reconstruction is keyhole surgery performed in a confined space. A technology-supported workflow called computer-assisted surgery (CAS) has become the standard for complex orbital traumatology in many hospitals. CAS technology has catalyzed the incorporation of personalized medicine in orbital reconstruction. The complete workflow consists of diagnostics, planning, surgery and evaluation. Advanced diagnostics and virtual surgical planning are techniques utilized in the preoperative phase to optimally prepare for surgery and adapt the treatment to the patient. Further personalization of the treatment is possible if reconstruction is performed with a patient-specific implant and several design options are available to tailor the implant to individual needs. Intraoperatively, visual appraisal is used to assess the obtained implant position. Surgical navigation, intraoperative imaging, and specific PSI design options are able to enhance feedback in the CAS workflow. Evaluation of the surgical result can be performed both qualitatively and quantitatively. Throughout the entire workflow, the concepts of CAS and personalized medicine are intertwined. A combination of the techniques may be applied in order to achieve the most optimal clinical outcome. The goal of this article is to provide a complete overview of the workflow for post-traumatic orbital reconstruction, with an in-depth description of the available personalization and CAS options.

Functional and Cosmetic Outcome after Reconstruction of Isolated, Unilateral Orbital Floor Fractures (Blow-Out Fractures) with and without the Support of 3D-Printed Orbital Anatomical Models

The present study aimed to analyze if a preformed "hybrid" patient-specific orbital mesh provides a more accurate reconstruction of the orbital floor and a better functional outcome than a standardized, intraoperatively adapted titanium implant. Thirty patients who had undergone surgical reconstruction for isolated, unilateral orbital floor fractures between May 2016 and November 2018 were included in this study. Of these patients, 13 were treated conventionally by intraoperative adjustment of a standardized titanium mesh based on assessing the fracture's shape and extent. For the other 17 patients, an individual three-dimensional (3D) anatomical model of the orbit was fabricated with an in-house 3D-printer. This model was used as a template to create a so-called "hybrid" patient-specific titanium implant by preforming the titanium mesh before surgery. The functional and cosmetic outcome in terms of diplopia, enophthalmos, ocular motility, and sensory disturbance trended better when "hybrid" patient-specific titanium meshes were used but with statistically non-significant differences. The 3D-printed anatomical models mirroring the unaffected orbit did not delay the surgery's timepoint. Nonetheless, it significantly reduced the surgery duration compared to the traditional method (58.9 (SD: 20.1) min versus 94.8 (SD: 33.0) min, p-value = 0.003). This study shows that using 3D-printed anatomical models as a supporting tool allows precise and less time-consuming orbital reconstructions with clinical benefits.